Genome-Wide Association Study of Acute Renal Graft Rejection.

Acute renal rejection is a major risk factor for chronic allograft dysfunction and long-term graft loss. We performed a genome-wide association study to detect loci associated with biopsy-proven acute T cell-mediated rejection occurring in the first year after renal transplantation. In a discovery cohort of 4127 European renal allograft recipients transplanted in eight European centers, we used a DNA pooling approach to compare 275 cases and 503 controls. In an independent replication cohort of 2765 patients transplanted in two European countries, we identified 313 cases and 531 controls, in whom we genotyped individually the most significant single nucleotide polymorphisms (SNPs) from the discovery cohort. In the discovery cohort, we found five candidate loci tagged by a number of contiguous SNPs (more than five) that was never reached in iterative in silico permutations of our experimental data. In the replication cohort, two loci remained significantly associated with acute rejection in both univariate and multivariate analysis. One locus encompasses PTPRO, coding for a receptor-type tyrosine kinase essential for B cell receptor signaling. The other locus involves ciliary gene CCDC67, in line with the emerging concept of a shared building design between the immune synapse and the primary cilium.

De novo kidney graft tumors: results from a multicentric retrospective national study.

De novo tumors in renal allografts are rare and their prevalence is underestimated. We therefore analyzed renal cell carcinomas arising in renal allografts through a retrospective French renal transplant cohort. We performed a retrospective, multicentric survey by sending questionnaires to all French kidney transplantation centers. All graft tumors diagnosed after transplantation were considered as de novo tumors. Thirty-two centers participated in this study. Seventy-nine tumors were identified among 41 806 recipients (Incidence 0.19%). Patients were 54 men and 25 women with a mean age of 47 years old at the time of diagnosis. Mean tumor size was 27.8 mm. Seventy-four (93.6%), 53 (67%) and 44 tumors (55.6%) were organ confined (T1-2), low grade (G1-2) and papillary carcinomas, respectively. Four patients died of renal cell carcinomas (5%). The mean time lapse between transplantation and RCC diagnosis was 131.7 months. Thirty-five patients underwent conservative surgery by partial nephrectomy (n = 35, 44.3%) or radiofrequency (n = 5; 6.3%). The estimated 5 years cancer specific survival rate was 94%. Most of these tumors were small and incidental. Most tumors were papillary carcinoma, low stage and low grade carcinomas. Conservative treatment has been preferred each time it was feasible in order to avoid a return to dialysis.

Efficacy and safety of early cyclosporine conversion to sirolimus with continued MMF-four-year results of the Postconcept study.

Calcineurin inhibitor (CNI) withdrawal has been used as a strategy to improve renal allograft function. We previously reported that conversion from cyclosporine A (CsA) to sirolimus (SRL) 3 months after transplantation significantly improved renal function at 1 year. In the Postconcept trial, 77 patients in the SRL group and 85 in the CsA group were followed for 48 months. Renal function (Cockcroft and Gault) was significantly better at month 48 (M48) in the SRL group both in the intent-to-treat population (ITT): 62.6 mL/min/1.73 m(2) versus 57.1 mL/min/1.73 m(2) (p = 0.013) and in the on-treatment population (OT): 67.5 mL/min/1.73 m(2) versus 57.4 mL/min/1.73 m(2) (p = 0.002). Two biopsy proven acute rejection episodes occurred after M12 in each group. Graft and patient survival were comparable (graft survival: 97.4 vs. 100%; patient survival: 97.4 vs. 97.6%, respectively). The incidence of new-onset diabetes was numerically increased in the SRL group (7 vs. 2). In OT, three cancers occurred in the SRL group versus nine in the CsA group and mean proteinuria was increased in the SRL group (0.42 ± 0.44 vs. 0.26 ± 0.37; p = 0.018). In summary, the renal benefits associated with conversion of CsA to SRL, at 3 months posttransplantation, in combination with MMF were maintained for 4 years posttransplantation.

Presentation and revascularization outcomes in patients with radiation-induced renal artery stenosis.

This study analyzed the initial presentation and revascularization outcomes of patients with radiation-induced renal artery stenosis, a rare complication of therapeutic irradiation. Of 11 patients with renal artery stenosis after irradiation, 7 patients fulfilled the following criteria: normotension before irradiation, radiation dose greater than 25 grays delivered to the renal arteries, associated perirenal radiation-induced lesions, and absence of arterial disease outside the radiation field. The median age at irradiation was 30 years, and the median local irradiation dose was 40 grays. The median time from irradiation to referral was 13 years. All patients were hypertensive at referral, with a median blood pressure (BP) of 171/102 mm Hg and median treatment score of two. The median glomerular filtration rate was 67 mL/min. Two patients had bilateral stenoses and 1 patient had stenosis affecting a single kidney. Stenoses were proximal in 6 patients and truncal in 1 patient, and all had the appearance of atherosclerotic stenosis. Percutaneous transluminal renal artery angioplasty (PTRA) was successful in 5 patients, but required multiple insufflations. PTRA failed in 1 patient, who subsequently underwent an aortorenal bypass. After a median follow-up of 36 months, 2 patients had died of noncardiovascular causes and 4 patients remained hypertensive, with a median BP of 136/85 mm Hg and median treatment score of two. No restenosis occurred, but aneurysms developed at the site of angioplasty in 1 patient. If hypertension occurs even decades after irradiation, a radiation-induced renal artery stenosis should be sought in patients who have undergone abdominal irradiation.

[Plasminogen activator inhibitor type 1: physiology and role in renal physiopathology]. / L'inhibiteur de type 1 des activateurs du plasminogène: physiologie et rôle en physiopathologie rénale.

Plasminogen activator inhibitor type 1 plays a prominent part in the regulation of extra and intra-vascular fibrinolysis through the inhibition of plasmin formation. In addition to its role in the resolution of blood clots, PAI-1 is involved in a variety of other biological processes including extracellular remodeling, cellular mobility, embryo implantation, development and tumoral proliferation. Moreover, PAI-1 is also implicated in various pathological processes such as thromboembolic diseases, atherosclerosis and fibrosis formation, particularly in the kidney and the lung. Inhibition of PAI-1 activity or of PAI-1 synthesis by specific antibodies, peptidic antagonists, antisens oligonucleotides or decoy oligonucleotides has been obtained in vitro but need to be evaluated in vivo. All these findings may have new therapeutical implications, explaining the importance of studies on PAI-1 production and regulation.

Tacrolimus-induced hemolytic uremic syndrome and end-stage renal failure after liver transplantation.

BACKGROUND: Hemolytic uremic syndrome (HUS) is a rare complication in solid organ transplantation. It can be associated with severe hypertension. Several risk factors have been identified including immunosuppressive drugs such as cyclosporin A and, more recently, tacrolimus. METHODS: Here we report a case of tacrolimus-induced HUS in a 61-yr-old woman after liver transplantation. Hypertension, microangiopathic anemia and end-stage renal failure occurred 2 yr after liver transplantation. RESULTS: At admission, she had malignant hypertension with a severe hypertensive retinopathy, renal failure (creatininemia: 800 micromol/L) and microangiopathic anemia (Hb: 7.3 g/dL, a low platelet count and elevated lactate dehydrogenase). At renal biopsy, histologic findings were ischemic and sclerotic glomeruli with hyaline thrombi, severe mesangiolysis and interstitial fibrosis. CONCLUSION: Despite steroid treatment, antihypertensive agents and fresh frozen plasma therapy, end-stage renal failure was observed and chronic hemodialysis treatment was required.